It is a common manufacturing practice to inject an expandable foam material, such as a polyurethane foam, into the double wall cabinet of a refrigeration appliance, such as a refrigerator or freezer, to provide a desired degree of thermal insulation to the appliance. Known foam injecting methods include mixing a predetermined amount of the starting chemicals and injecting them at a predetermined location within the double-wall of the cabinet from which location the foaming process essentially begins. The foaming mixture then expands within the double-wall of the cabinet flowing throughout and between the double-wall of the cabinet's two exterior side panels, exterior top and bottom panels, exterior back panel, and any interior rib panel. Before the start of the fill process, a venting hole is created at a predetermined location in the compartment cavity to release air trapped ahead of the advancing foam. Other venting holes may be required at different predetermined locations to avoid any pockets of trapped air, which cannot be filled with foam. Preheating of a compartment cavity may be necessary to increase the activity of the foaming mixture to flow throughout the cavity.
The prior foaming techniques often result in uneven distribution of the foam within the various contours and spaces of the double-wall cabinet, as well as the formation of air pockets, resulting in decreased insulation performance. In addition, the density of the foam material at various locations cannot be controlled and can vary widely.
Accordingly, an improved method for filling the cabinet of a consumer appliance with expandable foam is desirable.